I have friends in a professional cover band. It is not aginst the law to play them as a payed band,, only to record and sell with out copywrite permissions IE Royalities paid. In a jam session covers is what its about and then taking it to another place with each person being able to take a solo if desired.
“It’s like a Jab, you got the squeeze and you got the attack, you got the guitar and the emotion behind the song.
You can plug into a Marshall, but if you are not attacking it's just going to sound so-so. If the song doesn't grove, you are just bashing through chords” .
-- Mike Ness, Social Distortion